You could adapt the code from tendo's python library source
what they do is
for windows :
creating a file made of the executable absolute path (well it's a library, so in your case, you can just define an identifier, to prevent you from "i put the executable in 2 places")
- For windows: trying first to remove the file if existing, and if not creating the file with
os.O_CREAT | os.O_EXCL | os.O_RDWR
- For POSIX compatible systems: trying first to remove the file if existing and if not creating the file and acquiring a lock on it using
fcntl.LOCK_EX | fcntl.LOCK_NB
any failure mean the program is already running
and then you can use a defer action to remove the lock (on posix system) and delete the file
Go permit you to create both version wit a build comment to tell which file to compile depending on your OS so you have
for unix system
// +build !windows
package main
import (
"os"
"syscall"
)
func create_lock_file(filename string) (*os.File, error) {
file, err := os.OpenFile(filename, os.O_WRONLY, 0666)
if err != nil {
return nil, err
}
err = syscall.Flock(int(file.Fd()), syscall.LOCK_EX|syscall.LOCK_NB)
if err != nil {
return nil, err
}
return file, nil
}
for windows:
// +build !windows
package main
import (
"os"
)
func create_lock_file(filename string) (*os.File, error) {
if _, err := os.Stat(filename); err == nil {
err = os.Remove(filename)
if err != nil {
return nil, err
}
}
return os.OpenFile(filename, os.O_CREATE|os.O_EXCL|os.O_RDWR, 0666)
}
and a test
package main
import (
"fmt"
"time"
)
func main() {
_, err := create_lock_file("plop.lock")
if err != nil {
fmt.Println("error ", err.Error())
}
time.Sleep(10 * time.Second)
fmt.Println("end ")
}
I've started a library out of it that you can find here